inode.c

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	}
	/*
	 * This is done outside the above if statement so that the
	 * check can be done for block group #0.
	 */
	if (scan->current_block == 0) {
		if (scan->scan_flags & EXT2_SF_SKIP_MISSING_ITABLE) {
			goto force_new_group;
		} else
			return EXT2_ET_MISSING_INODE_TABLE;
	}


	/*
	 * Have we run out of space in the inode buffer?  If so, we
	 * need to read in more blocks.
	 */
	if (scan->bytes_left < scan->inode_size) {
		memcpy(scan->temp_buffer, scan->ptr, scan->bytes_left);
		extra_bytes = scan->bytes_left;

		retval = get_next_blocks(scan);
		if (retval)
			return retval;
#if 0
		/*
		 * XXX test  Need check for used inode somehow.
		 * (Note: this is hard.)
		 */
		if (is_empty_scan(scan))
			goto force_new_group;
#endif
	}

	retval = 0;
	if (extra_bytes) {
		memcpy(scan->temp_buffer+extra_bytes, scan->ptr,
		       scan->inode_size - extra_bytes);
		scan->ptr += scan->inode_size - extra_bytes;
		scan->bytes_left -= scan->inode_size - extra_bytes;

#if BB_BIG_ENDIAN
		if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
		    (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
			ext2fs_swap_inode_full(scan->fs,
				(struct ext2_inode_large *) inode,
				(struct ext2_inode_large *) scan->temp_buffer,
				0, bufsize);
		else
#endif
			*inode = *((struct ext2_inode *) scan->temp_buffer);
		if (scan->scan_flags & EXT2_SF_BAD_EXTRA_BYTES)
			retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
		scan->scan_flags &= ~EXT2_SF_BAD_EXTRA_BYTES;
	} else {
#if BB_BIG_ENDIAN
		if ((scan->fs->flags & EXT2_FLAG_SWAP_BYTES) ||
		    (scan->fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
			ext2fs_swap_inode_full(scan->fs,
				(struct ext2_inode_large *) inode,
				(struct ext2_inode_large *) scan->ptr,
				0, bufsize);
		else
#endif
			memcpy(inode, scan->ptr, bufsize);
		scan->ptr += scan->inode_size;
		scan->bytes_left -= scan->inode_size;
		if (scan->scan_flags & EXT2_SF_BAD_INODE_BLK)
			retval = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
	}

	scan->inodes_left--;
	scan->current_inode++;
	*ino = scan->current_inode;
	return retval;
}

errcode_t ext2fs_get_next_inode(ext2_inode_scan scan, ext2_ino_t *ino,
				struct ext2_inode *inode)
{
	return ext2fs_get_next_inode_full(scan, ino, inode,
						sizeof(struct ext2_inode));
}

/*
 * Functions to read and write a single inode.
 */
errcode_t ext2fs_read_inode_full(ext2_filsys fs, ext2_ino_t ino,
				 struct ext2_inode * inode, int bufsize)
{
	unsigned long	group, block, block_nr, offset;
	char		*ptr;
	errcode_t	retval;
	int		clen, i, inodes_per_block, length;
	io_channel	io;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	/* Check to see if user has an override function */
	if (fs->read_inode) {
		retval = (fs->read_inode)(fs, ino, inode);
		if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
			return retval;
	}
	/* Create inode cache if not present */
	if (!fs->icache) {
		retval = create_icache(fs);
		if (retval)
			return retval;
	}
	/* Check to see if it's in the inode cache */
	if (bufsize == sizeof(struct ext2_inode)) {
		/* only old good inode can be retrieve from the cache */
		for (i=0; i < fs->icache->cache_size; i++) {
			if (fs->icache->cache[i].ino == ino) {
				*inode = fs->icache->cache[i].inode;
				return 0;
			}
		}
	}
	if ((ino == 0) || (ino > fs->super->s_inodes_count))
		return EXT2_ET_BAD_INODE_NUM;
	if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
		inodes_per_block = fs->blocksize / EXT2_INODE_SIZE(fs->super);
		block_nr = fs->image_header->offset_inode / fs->blocksize;
		block_nr += (ino - 1) / inodes_per_block;
		offset = ((ino - 1) % inodes_per_block) *
			EXT2_INODE_SIZE(fs->super);
		io = fs->image_io;
	} else {
		group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
		offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
			EXT2_INODE_SIZE(fs->super);
		block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
		if (!fs->group_desc[(unsigned)group].bg_inode_table)
			return EXT2_ET_MISSING_INODE_TABLE;
		block_nr = fs->group_desc[(unsigned)group].bg_inode_table +
			block;
		io = fs->io;
	}
	offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);

	length = EXT2_INODE_SIZE(fs->super);
	if (bufsize < length)
		length = bufsize;

	ptr = (char *) inode;
	while (length) {
		clen = length;
		if ((offset + length) > fs->blocksize)
			clen = fs->blocksize - offset;

		if (block_nr != fs->icache->buffer_blk) {
			retval = io_channel_read_blk(io, block_nr, 1,
						     fs->icache->buffer);
			if (retval)
				return retval;
			fs->icache->buffer_blk = block_nr;
		}

		memcpy(ptr, ((char *) fs->icache->buffer) + (unsigned) offset,
		       clen);

		offset = 0;
		length -= clen;
		ptr += clen;
		block_nr++;
	}

#if BB_BIG_ENDIAN
	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
	    (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
		ext2fs_swap_inode_full(fs, (struct ext2_inode_large *) inode,
				       (struct ext2_inode_large *) inode,
				       0, length);
#endif

	/* Update the inode cache */
	fs->icache->cache_last = (fs->icache->cache_last + 1) %
		fs->icache->cache_size;
	fs->icache->cache[fs->icache->cache_last].ino = ino;
	fs->icache->cache[fs->icache->cache_last].inode = *inode;

	return 0;
}

errcode_t ext2fs_read_inode(ext2_filsys fs, ext2_ino_t ino,
			    struct ext2_inode * inode)
{
	return ext2fs_read_inode_full(fs, ino, inode,
					sizeof(struct ext2_inode));
}

errcode_t ext2fs_write_inode_full(ext2_filsys fs, ext2_ino_t ino,
				  struct ext2_inode * inode, int bufsize)
{
	unsigned long group, block, block_nr, offset;
	errcode_t retval = 0;
	struct ext2_inode_large temp_inode, *w_inode;
	char *ptr;
	int clen, i, length;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	/* Check to see if user provided an override function */
	if (fs->write_inode) {
		retval = (fs->write_inode)(fs, ino, inode);
		if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
			return retval;
	}

	/* Check to see if the inode cache needs to be updated */
	if (fs->icache) {
		for (i=0; i < fs->icache->cache_size; i++) {
			if (fs->icache->cache[i].ino == ino) {
				fs->icache->cache[i].inode = *inode;
				break;
			}
		}
	} else {
		retval = create_icache(fs);
		if (retval)
			return retval;
	}

	if (!(fs->flags & EXT2_FLAG_RW))
		return EXT2_ET_RO_FILSYS;

	if ((ino == 0) || (ino > fs->super->s_inodes_count))
		return EXT2_ET_BAD_INODE_NUM;

	length = bufsize;
	if (length < EXT2_INODE_SIZE(fs->super))
		length = EXT2_INODE_SIZE(fs->super);

	if (length > (int) sizeof(struct ext2_inode_large)) {
		w_inode = xmalloc(length);
	} else
		w_inode = &temp_inode;
	memset(w_inode, 0, length);

#if BB_BIG_ENDIAN
	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
	    (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
		ext2fs_swap_inode_full(fs, w_inode,
				       (struct ext2_inode_large *) inode,
				       1, bufsize);
	else
#endif
		memcpy(w_inode, inode, bufsize);

	group = (ino - 1) / EXT2_INODES_PER_GROUP(fs->super);
	offset = ((ino - 1) % EXT2_INODES_PER_GROUP(fs->super)) *
		EXT2_INODE_SIZE(fs->super);
	block = offset >> EXT2_BLOCK_SIZE_BITS(fs->super);
	if (!fs->group_desc[(unsigned) group].bg_inode_table)
		return EXT2_ET_MISSING_INODE_TABLE;
	block_nr = fs->group_desc[(unsigned) group].bg_inode_table + block;

	offset &= (EXT2_BLOCK_SIZE(fs->super) - 1);

	length = EXT2_INODE_SIZE(fs->super);
	if (length > bufsize)
		length = bufsize;

	ptr = (char *) w_inode;

	while (length) {
		clen = length;
		if ((offset + length) > fs->blocksize)
			clen = fs->blocksize - offset;

		if (fs->icache->buffer_blk != block_nr) {
			retval = io_channel_read_blk(fs->io, block_nr, 1,
						     fs->icache->buffer);
			if (retval)
				goto errout;
			fs->icache->buffer_blk = block_nr;
		}


		memcpy((char *) fs->icache->buffer + (unsigned) offset,
		       ptr, clen);

		retval = io_channel_write_blk(fs->io, block_nr, 1,
					      fs->icache->buffer);
		if (retval)
			goto errout;

		offset = 0;
		ptr += clen;
		length -= clen;
		block_nr++;
	}

	fs->flags |= EXT2_FLAG_CHANGED;
errout:
	if (w_inode && w_inode != &temp_inode)
		free(w_inode);
	return retval;
}

errcode_t ext2fs_write_inode(ext2_filsys fs, ext2_ino_t ino,
			     struct ext2_inode *inode)
{
	return ext2fs_write_inode_full(fs, ino, inode,
				       sizeof(struct ext2_inode));
}

/*
 * This function should be called when writing a new inode.  It makes
 * sure that extra part of large inodes is initialized properly.
 */
errcode_t ext2fs_write_new_inode(ext2_filsys fs, ext2_ino_t ino,
				 struct ext2_inode *inode)
{
	struct ext2_inode	*buf;
	int			size = EXT2_INODE_SIZE(fs->super);
	struct ext2_inode_large	*large_inode;

	if (size == sizeof(struct ext2_inode))
		return ext2fs_write_inode_full(fs, ino, inode,
					       sizeof(struct ext2_inode));

	buf = xmalloc(size);

	memset(buf, 0, size);
	*buf = *inode;

	large_inode = (struct ext2_inode_large *) buf;
	large_inode->i_extra_isize = sizeof(struct ext2_inode_large) -
		EXT2_GOOD_OLD_INODE_SIZE;

	return ext2fs_write_inode_full(fs, ino, buf, size);
}


errcode_t ext2fs_get_blocks(ext2_filsys fs, ext2_ino_t ino, blk_t *blocks)
{
	struct ext2_inode	inode;
	int			i;
	errcode_t		retval;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (ino > fs->super->s_inodes_count)
		return EXT2_ET_BAD_INODE_NUM;

	if (fs->get_blocks) {
		if (!(*fs->get_blocks)(fs, ino, blocks))
			return 0;
	}
	retval = ext2fs_read_inode(fs, ino, &inode);
	if (retval)
		return retval;
	for (i=0; i < EXT2_N_BLOCKS; i++)
		blocks[i] = inode.i_block[i];
	return 0;
}

errcode_t ext2fs_check_directory(ext2_filsys fs, ext2_ino_t ino)
{
	struct	ext2_inode	inode;
	errcode_t		retval;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (ino > fs->super->s_inodes_count)
		return EXT2_ET_BAD_INODE_NUM;

	if (fs->check_directory) {
		retval = (fs->check_directory)(fs, ino);
		if (retval != EXT2_ET_CALLBACK_NOTHANDLED)
			return retval;
	}
	retval = ext2fs_read_inode(fs, ino, &inode);
	if (retval)
		return retval;
	if (!LINUX_S_ISDIR(inode.i_mode))
		return EXT2_ET_NO_DIRECTORY;
	return 0;
}